A national study shows Washington parents are choosing not to vaccinate their kindergartners at a rate higher than anywhere else in the country.

The rate — 6.2 percent — is below national standards and endangers residents, especially children who are not yet fully immunized, state health officials say.

They point to recent cases of whooping cough — two babies died of the disease in Washington in 2010 — and measles, which is highly contagious. A Kitsap County 2-year-old was diagnosed with measles last week.

The study released Thursday by the Centers for Disease Control and Prevention (CDC) is the first time states’ immunization rates have been ranked.

“Most of today’s parents weren’t around to see how bad diseases like measles and whooping cough were before vaccines helped bring them under control,” state Secretary of Health Mary Selecky said in a news release. “We’ve done a good job fending off those diseases with vaccines, but we can’t be complacent; we’re seeing them start to make a comeback and too many of our kids are vulnerable.”

The low vaccination rate of the state’s children is the subject of a new state law and has the attention of the Bill & Melinda Gates Foundation, which will soon announce a three-year grant aimed at increasing immunizations in the Northwest.

State legislators passed a bill last session that will require parents to provide a signed note from a doctor in order to enroll a kindergarten student who has not been fully immunized. That law takes effect July 22 and will address the state’s current, more lax requirements. All it takes now to opt out of immunizations is a parent’s signature.

Opt-out rates

The CDC study ranked states by the percentage of kindergartners opting out of all or some immunizations in 2009-2010. Washington had the most, followed by three other states with higher-than 5 percent opt-out rates: Vermont, Alaska and Oregon. The national rate is less than 2 percent. Alabama and Tennessee had rates of 0.5 percent.

In King County, according to state data, about 5.5 percent of kindergartners opt out of at least one vaccination. Some counties reported much higher rates. Nearly 20 percent of Ferry County kindergartners opted out in 2009-2010, the highest rate in the state.

“Six percent is something to worry about. They’re really high,” said Michele Roberts, a spokeswoman for the state’s immunization program.

Barbara Loe Fisher, who heads the National Vaccine Information Center, an anti-immunization group based in Virginia, said people in states that make opting out easy for parents are “generally” as healthy as people elsewhere.

Parents choosing to opt out of required vaccines have educated themselves about risks, or they’re concerned about a reaction their child had to an early immunization, she said. Some people also opt out for religious reasons.

“There’s a lot more information available to the public now. I think doctors and health-care officials are going to have to get used to the educated health-care consumer,” she said.

Focus on doctors

The Bill & Melinda Gates Foundation, which works to boost vaccination rates around the world, will soon announce a new, local program that will focus on educating doctors, said David Bley, director of the foundation’s Pacific Northwest Initiative.

The three-year Vaccination Northwest program, which will be a collaboration with Group Health and local public-health officials, will give doctors evidence and data they need to answer parents’ questions and concerns about vaccination, said Joe Turcotte, communication director for Group Health Foundation. “Every survey out there shows that providers are sort of overwhelmed by the questions they get from parents,” he said.

Another arm of the project will look for more effective ways to get scientific information directly to parents.

Group Health Foundation will ante up $1 million for the project. The Gates Foundation’s contribution hasn’t been finalized yet.